Island



(No'ModeL) P. ARMINGTON.

0UT0PF PISTON VALVE.

No. 378,642. Patented Feb. 28, 1888.

N PETERS. Phmo-Lilhngmp UNIT D STATES PARDON ARMINGTON, OF PROVIDENCE, RHODE ISLAND.

Parent @FNCEE.

CUT-OFF PlS'i'ON VALl/E.

SPECIFICATION forming part of Letters Patent No. 378,642, dated February 28, 1888.

Application filed May 3, 1887. Serial No. 236,907. (No model.)

To aZZ whom it may concern:

Be it known that I, PARDON ARMmo'roN, of Providence, county or Providence,and State of Rhode Island, have invented an Improvement in Gut-Off Piston-Valves, of which the following description, in connection with the accompanying drawings, is a specification, like letters on the drawings representing like parts.

This invention relates to steam-valves, and is embodied in a pistonvalve especially de signed to be used in engines wherein a high speed is desired.

The object of my invention is to provide a steam-engine with piston-valves, whereby a maximum quantity of steam is admitted to the engine cylinder with a minimum stroke of the piston-valve, and I accomplish my object, as herein shown, by providing the main pistonvalve with auxiliary ports and passages, which establish a communication between the steamchest and the main port-opening of the main piston valve, the said auxiliary ports being controlled by an auxiliary piston-valve fitted within and having a bearing upon the inner surface of the main piston-valve.

My invention therefore consists, essentially, in a steam-engine, of a main cylinder and a valve'cylinder, combined with a main pistonvalve located in said valve-cylinder, and provided with a main port-opening and an auxiliary port-opening connected to the said main port-0pening, and with an auxiliary pistonvalve movable within the main piston-valve and provided with a port to register with the auxiliary port-opening of the main piston; valve, substantially as will be described.

Figure 1 is a longitudinal section of a sui'fr cient portion of an engine provided with my improved valves to enable my invention to be understood, the piston in the cnginecylinder being in elevation; Fig. 2, a section of Fig. 1, on line a: 00, through the main valve; Fig. 3, a section of Fig. 1,0n line a: w,through the main piston-valve,looking toward the right; Fig. 4, a section of the main pistonvalve on line y y, and Fig. 5 a section of the auxiliary pistonvalve on line 3 y.

The main engine cylinder, as shown, has cast integral within it two valve-cylinders, ac, located within the steam-chest formed above the engine-cylinder by the cap A.

The valve-cylinders a a are provided with piston-valves a a, respectively open at their inner ends and closed at their outer ends, as herein shown, the said piston-valves, in the present instance, taking steam from the center of the steam-chest and exhausting it through ports a a at opposite ends of the steam-chest, the said piston-valves being connected by rods a, so that they move-in unison when operated by valve-gearing to which the valve-rod a is connected, the said valve-rod being made hollow, for a purpose to be hereinafter described.

Each piston-valve a a, as shown, has an annular channel, b, constituting the main portopening to the engine-cylinder, and auxiliary channels 0", connected with the channel I) by an annular passage, b the said auxiliary channels constituting auxiliary port-openings to the enginecylindcr.

The main and auxiliary port-openings Z) Z) of the Valve a a are controlled by auxiliary piston-valves I) b, respectively,the said auxiliary pistonvalves being open at both ends, as shown.

Each auxiliary valve is provided with a cross-bar, I), (see Fig. 5,) through which is ex tended a rod, b, which is fastened. or clamped to the said cross-bars, as shown, by nuts b the rod b forming the val verod for the auxiliary piston-valves.

The valverod b as herein shown, is extended through the head 0 of the main piston-valve c and through the hollow valve-rod ahand is connected to the cutoff mechanism of the engine to operate the said auxiliary piston-valves and out off the admission of steam to the en gi lie-cylinder.

Each auxiliary pistoirvalve is preferably provided on its interior with strengtheningribs 0. (See Fig. 5.)

I have herein shown two auxiliary portopenings, b and each of said portopenings is equal in cross-section or area to onethird the cross section or area of the main port-opening b, so that the auxiliary piston-valve, which is provided with annular channels e to co'operate with the port-openings this required to be moved only sufficient distance to uncover or open the said auxiliary ports, the main portopening being at such time only one-third opened or uncovered by the auxiliary piston- LOO 3&3

' valve b is about to open the main and auxiliary ports in the main piston-valve 64 the said auxiliary valve moving in the direction of arrow 20, and at the same time the main valve a is being moved in the direction of arrow 21. WVhen the auxiliary piston-valve b has uncovered the auxiliary port-openings, the maximum amount of steam is admitted into the port-opening b, from which it passes into the engine-cylinder. As the auxiliary port-openings b are being closed, it will befound that on the further movement of the auxiliary pistonvalve, the port-openings 6 being wider than the auxiliary ports Zfiin the main valve, a sufficient area of the several openings is maintained until the closing of the port e by the main valve, as a to maintain a constant or nearly constant pressure of steam in the engine-cylinder to the point of cut off.

The main and auxiliary piston-valves are shown as taking steam from the center of the valve chest and exhausting it at the ends thereof; but instead of the arrangement shown I may reverse the position of the valves, so that the said valves will take steam at the end of the valve-chest and exhaust it at the center of the valve chest.

I claim- 1. In a steam-engine, a main cylinder and a valve-cylinder, combined with a main pistonvalve located in said valve-cylinder, and provided with a main port-opening, b, and an auxiliary portopening', b", and passage 1), connecting the said port-openings, and with an auxiliary piston-valve movable within the main piston-valve and provided with a port to register with the auxiliaryport-opening of the main piston-valve, substantially as described.

2. In a steam-engine, a main cylinder and a valve-cylinder, combined with a main pistonvalve located in said valve-cylinder, and provided with a main port-opening, b, and an auxiliary port-opening, b and passage b connecting the said port-openings, and with an auxiliary valve movable within the main piston-valve to control the said main and auxiliary port-openings, substantially as described.

3. In a stcanreugine, a main cylinder and a valve-cylinder connected to each endof the said main cylinder, combined with a main piston-valve located in each of said valvecylinders, and provided with a main port-opening and an auxiliary port opening connected to the said main port-opening, and with an auxiliary pistonvalve movable within each main pistonvalve and provided with a port to register with the auxiliary port-opening of the main piston-valve, the said main auxiliary pistonvalves being connected together, substantially as described.

In testimony whereofl have signed my name to this specification in the presence of two subscribing witnesses.

PARDON ARMINGTON.

Witnesses:

JAS. H. CHURCHILL, FRED L. EMERY. 

